package com.qiudao.basestudy.util;

import org.apache.commons.lang3.StringUtils;
import org.apache.tomcat.util.codec.binary.Base64;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.util.WebUtils;
import sun.misc.BASE64Decoder;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;
import java.math.BigInteger;

/**
 * Description: 编码工具类
 *  实现aes加密、解密
 * @author: gdc
 * @date: 2019/9/1
 * @version 1.0
 */
public class EncryptUtils {
    private static final Logger logger = LoggerFactory.getLogger(WebUtils.class);

    /**
     * 密钥,此长度必须是16位
     */
    private static final String KEY = "1qazXSW@4rfvBGT%";

    /**
     * 算法
     */
    private static final String ALGORITHMSTR = "AES/ECB/PKCS5Padding";


    /**
     * aes解密
     *
     * @param encrypt 内容
     * @return
     * @throws Exception
     */
    public static String aesDecrypt(String encrypt) throws Exception {
        return aesDecrypt(encrypt, KEY);
    }

    /**
     * aes加密
     *
     * @param content
     * @return
     * @throws Exception
     */
    public static String aesEncrypt(String content) throws Exception {
        return aesEncrypt(content, KEY);
    }

    /**
     * 将byte[]转为各种进制的字符串
     *
     * @param bytes byte[]
     * @param radix 可以转换进制的范围，从Character.MIN_RADIX到Character.MAX_RADIX，超出范围后变为10进制
     * @return 转换后的字符串
     */
    public static String binary(byte[] bytes, int radix) {
        return new BigInteger(1, bytes).toString(radix);// 这里的1代表正数
    }

    /**
     * base 64 encode
     *
     * @param bytes 待编码的byte[]
     * @return 编码后的base 64 code
     */
    public static String base64Encode(byte[] bytes) {
        return Base64.encodeBase64String(bytes);
    }

    /**
     * base 64 decode
     *
     * @param base64Code 待解码的base 64 code
     * @return 解码后的byte[]
     * @throws Exception
     */
    public static byte[] base64Decode(String base64Code) {
        try {
            return StringUtils.isEmpty(base64Code) ? null : new BASE64Decoder().decodeBuffer(base64Code);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }


    /**
     * AES加密
     *
     * @param content    待加密的内容
     * @param encryptKey 加密密钥
     * @return 加密后的byte[]
     * @throws Exception
     */
    public static byte[] aesEncryptToBytes(String content, String encryptKey) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            kgen.init(128);
            Cipher cipher = Cipher.getInstance(ALGORITHMSTR);
            cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(encryptKey.getBytes(), "AES"));

            return cipher.doFinal(content.getBytes("utf-8"));
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }


    /**
     * AES加密为base 64 code
     *
     * @param content    待加密的内容
     * @param encryptKey 加密密钥
     * @return 加密后的base 64 code
     * @throws Exception
     */
    public static String aesEncrypt(String content, String encryptKey) {
        try {
            return base64Encode(aesEncryptToBytes(content, encryptKey));
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * AES解密
     *
     * @param encryptBytes 待解密的byte[]
     * @param decryptKey   解密密钥
     * @return 解密后的String
     * @throws Exception
     */
    public static String aesDecryptByBytes(byte[] encryptBytes, String decryptKey) {
        byte[] decryptBytes = null;
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            kgen.init(128);

            Cipher cipher = Cipher.getInstance(ALGORITHMSTR);
            cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(decryptKey.getBytes(), "AES"));
            decryptBytes = cipher.doFinal(encryptBytes);
            return new String(decryptBytes);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }


    /**
     * 将base 64 code AES解密
     *
     * @param encryptStr 待解密的base 64 code
     * @param decryptKey 解密密钥
     * @return 解密后的string
     * @throws Exception
     */
    public static String aesDecrypt(String encryptStr, String decryptKey) {
        try {
            return StringUtils.isEmpty(encryptStr) ? null : aesDecryptByBytes(base64Decode(encryptStr), decryptKey);
        } catch (Exception e) {
            logger.error("密码格式错误!");
        }
        return null;
    }

    public static void main(String[] args) throws Exception {
        String content = "goldcard";
        System.out.println("加密前：" + content);

        System.out.println("加密密钥和解密密钥：" + KEY);

        String encrypt = aesEncrypt(content, KEY);
        System.out.println("加密后：" + encrypt);

        String decrypt = aesDecrypt(encrypt, KEY);
        System.out.println("解密后：" + decrypt);
    }
}